In a state-of-art record carrier, such as CD-R, CD-RW or MO disk, a wobbled pregroove is typically provided for marking ATIP (absolute time in pregroove) codes. The ATIP codes provide a basis for the data recording apparatus to read or write information on the record carrier. The prior arts regarding the wobbled pregroove and ATIP codes may be found in the U.S. Pat. No. 5,226,027 and “Orange Book”, 3rd edition, published by Philip corp. in 1997.
However, based on the prior arts, writing error and interruption still occur during writing of data on the record carrier. So a portion of or entire record carrier cannot be read due to the writing errors. The major possible reasons for the unsuccessful recording of data on the storage unit of record carrier include the defects, scratches and stains which are not detected prior to the writing of data.
These reasons are described summarily as follows. (1) Wrong ATLP codes with inconsistent CIRC checksum are marked on the record carrier. (2) Format not complying with the standard format specified in “Orange Book”. (3) Scratches are accidentally made over the substrate of the record carrier after the manufacture of the record carrier. (4) The finger print, dust and stains imposed over the record carrier after the manufacture of the record carrier. (5) The scratches are made over the reflective layer of the record carrier after the manufacture of the record carrier.
Aforesaid defects of (1), (2) affect the quality of the record carrier significantly and defect in (2) mainly results from the issues of material and procedure control during the manufacturing. The defects due to the reason (2) can not be easily detected by the reflected signal from the surface of record carrier. However, by detecting error occurred in reading ATIP codes, the detection of the defects of (1) and (2) can be accomplished easily. Moreover, the detection of ATIP codes can be implemented by using the current information record system. Therefore, detecting of ATIP codes can be used as index indicative of the quality of record carrier.
The defects of (3), (4) and (5) can be detected by the reflected signal from the surface of the record carrier.